Several medical procedures necessitate puncture of subcutaneous blood vessels and therefore require the precise localization of these. Most commonly the localization is done visually or by palpitating the selected area, but this can be hampered if the recipient of the medical treatment has small, deep-lying vessels, is obese, is an infant, is anaemic, has a dark skin complexion, experiences vein contraction due to stress or suffers from burns, blood loss, dehydration or varicose veins. Vein wall thickening or scar tissue due to repeated treatment with venous access devices may also hamper cannulation procedures. Missing the vessel during injection can be unpleasant as this requires repeated stabbing, but can also have serious consequences such as extra vascular hemorrhaging if the vessel is punctured or tissue toxicity, if for example injecting chemotherapeutic agents.
Numerous inventions have been provided for localization of blood vessels in the prior art. In U.S. Pat. No. 5,608,210 Esparza describes an invention utilizing infrared light for aiding in locating a vein for insertion of a hypodermic needle. The operator performing the injection wears a headpiece which in front of one or both eyes comprises an infrared light source, a video camera and a monitor screen. This is unpractical and limits the mobility of the operator of the device.
In U.S. Pat. No. 6,178,340, the main technical components of the invention are the same as in the above mentioned invention. However, the components of the invention described in U.S. Pat. No. 6,178,340 are comprised within a frame and placed on a stand between the operator of the device and the recipient. The operator puts on two-color filter glasses to achieve a three dimensional effect of the generated image. Again, the requirement of eyewear is unpractical, and the use of a stand limits the flexibility and speed of the use of the device.
Reynolds describes in U.S. Pat. Appl. Pub. 2005/0119546 an invention which is placed directly upon the recipient. Although the invention includes light emitting diodes (LEDs) and a display, this invention does not provide the operator with a real time video image of the subcutaneous blood vessels and cannot display the insertion of, for example a hypodermic needle, into such a vessel.
There still exists a need for a small, practical, real time imaging system for visualizing subcutaneous blood filled structures which is intuitive in use, does not restrain the movements of either the operator of the device or the recipient of any medical treatment, which might benefit from the use of the device, and is usable in nearly any setting.